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Short-term borrowings (Details 2) (Short-term debt [Member], Cascade Natural Gas Corporation [Member], Revolving credit agreement [Member]) | Dec. 31, 2013
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Short-term debt [Member] | Cascade Natural Gas Corporation [Member] | Revolving credit agreement [Member] |
Short-term debt [Line Items] |
Weighted average interest rate | 3.30%
Ratio of total debt to total capitalization as specified in debt convenants. | 65.00%

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- Definition Weighted average interest rate of debt outstanding. + References No definition available. + Details
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Balance Type: | na
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- Details
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